The invention relates to esters derived from fatty acids and juvenoid alcohols, a method of their preparation and use for reduction of insect population density.
The studies of juvenoids, compounds imitating the effect of natural insect juvenile hormone on insect development and reproduction, have represented an intensively studied field since mid-sixties of this century. A number of monographies and reviews (e.g. Slxc3xa1ma K., Roma{haeck over (n)}uk M, {haeck over (S)}orm F.: Insect Hormones and Bioanalogues, Springer, 1974; Henrick C. A.: Juvenoids; in the book Agrochemicals from Natural Products (C. R. A. Godfrey, ed.), pp. 147-213 (1995); Wimmer Z., Rejzek M., Zarevxc3xacka M., Kuldovxc3xa1 J., Hrdý I., N{haeck over (e)}mec V., Roma{haeck over (m)}uk M.: J. Chem. Ecol. 23, 605-628 (1997)) support this statement. Recently, the attention has also been focused on a modified type of the compounds, which display the effect on insect development and reproduction, on juvenogens (Slxc3xa1ma K., Roma{haeck over (n)}uk M.: Insect Biochem. 6, 579-586 (1976); Wimmer Z., Rejzek M., Zarevxc3xacka M., Kuldovxc3xa1 J., Hrdý I., N{haeck over (e)}mec V., Roma{haeck over (n)}uk M.: J. Chem. Ecol. 23, 605-628 (1997)). During designing and developing of these new compounds, selected ways of transformation of certain functionalities in the juvenoid molecules have been applied, resulting in a formation of a new functionality, e.g. ester functionality, replacing of the original functionality, e.g. alcoholic functionality, through which transformation physico-chemical properties of the new compound are different from the physico-chemical properties of the original compound. Changes in the physico-chemical properties of the compounds are connected with possible changes of practical application of the new compound as well.
1. The subjects of this invention are esters derived from fatty acids and juvenoid alcohols of the general formula I, 
in which X is oxygen or the NH group,
Y is the NH group or oxygen,
R is methyl, ethyl, 1-propyl, 2-methylethyl or propargyl and
Rxe2x80x2 is a saturated or an unsaturated alkyl with 4 to 22 carbon atoms.
2. The esters derived from fatty acids and juvenoid alcohols claimed in the claim 1 are prepared using a method that the juvenoid alcohol of the general formula II, 
in which X is the oxygen atom or the NH group,
Y is the NH group or the oxygen atom,
R is methyl, ethyl, 1-propyl, 2-methylethyl or propargyl is allowed to react with the chloride of a fatty acid of the general formula III,
Rxe2x80x2COClxe2x80x83xe2x80x83(III)
in which Rxe2x80x2 is a saturated or an unsaturated allyl with 4 to 22 carbon atoms, under the continuous stirring, at 0 to 70xc2x0 C., using a convenient solvent, as toluene, xylene or benzene and under the presence of a base catalyst, as triethylamine, pyridine or quinoline.
3. The esters derived from fatty acids and juvenoid alcohols claimed in claim 1 are used for the insect population density control, with special focus on the control of insects of the orders Isoptera, Blattodea, Diptera, Hymenoptera, Orthoptera, Coleoptera, and Lepidoptera. The esters derived from fatty acids and juvenoid alcohols claimed in the claim 1 display different chemical structure compared with the chemical structure of the original juvenoids and display also different physico-chemical properties compared with the properties of the original juvenoids, especially their melting points, through which they display different volatility and polarity, and these differences enable different way of practical application of the compounds claimed in the claim 1 against target insect species, and the esters derived from fatty acids and juvenoid alcohols claimed in claim 1 display higher stability in comparison with the stability of the original juvenoids and are responsible for improved dosage of the compounds claimed in the claim 1 during the screening against insect species. The compounds claimed in the claim 1 also enable a more effective way of practical application and due to their improved physico-chemical properties they also display a longer effect under the field conditions. The compounds claimed in the claim 1 are environmentally safe compounds, which are metabolized in a way through which no toxic residues, persistent in the nature, are left, which display no toxicity towards warm-blooded animals, fish or microorganisms living in water.
Examples are given in the following paragraphs, which make clear the way of preparation of the compounds claimed in the claim 1 of the general formula I.